Mond duval



(No Model.) 2 Sheets-Sheet 1. I

M. L. E. DUVAL. AUTOMATIC REGULATOR FOR AIR BRAKES.

' No. 486,703. Patented Nov. 22,1892.

(No Model.) 2 Sheets-Sheet 2.

. M. L. E. DUVAL.

AUTOMATIG REGULATOR FOR AIR BRAKES, No. 486,703. Patented Nov. 22, 1892.

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llllll-llllllllh 1 22512; I V jr zveiazr UNITED STATES PATENT ()FFICE.

MARTIN LEONARD EDMOND DUVAL, OF PARIS, FRANCE, ASSIGNOR TO THE COMPAGNIE DE FIVES-LILLE, OF SAME PLACE.

AUTOMATIC REG U LATOR FOR Al R-BRAKES.

SIECIFICA'IION forming part of Letters Patent No. 486,703, dated November 22, 1892.

Application filed February 18, 1892. Serial No. 422,028. (No model.)

To all whom it may concern: setting of the brakes applies, also, to the re- Be it known that I, MARTIN LEONARD ED- leasing of the same, which is eifected by the MOND DUVAL, a resident of Paris, in the Rere-establishment of pressure in the main conpublic of France, have invented a new and duit by putting it in communication with the 55 useful Improvementin AutomaticRegulators air-reservoir of the pump.

for Air-Brakes, which improvement is fully The object of the present invention is to set forth in the following specification. insure. in the various conditions that occur Apparatus heretofore employed forstopping the simultaneous action of the brakes withrailway-cars act by means of air compressed out'detriment to the promptness which is 60 [O by a pump on the locomotive or bya vacuum necessary, and the arrangement herein deproduced by a steam-ejector also carried by scribed permits this important result to be the locomotive. In both systems each vehiobtained. As a matter of example I have in (316 is provided with a brake apparatus cornthe drawings accompanying this specification posed, essentially,of a cylinder having a pisshown devices constructed in accordance with 65 I5 ton acting upon a brake-rod and a distributhe invention.

ting apparatus or triple valve, which is of dif- Figure 1 is a vertical section. Fig. 2 is a ferent forms, according to the system of which plan view, partly in section, on line x y z of it is a part, and the operation of which con- Fig. 1. Fig. 3 is a detail view showing a v trols the air acting on the piston. All brake modification; Fig. 4, a cross-sectionthereof; 7o apparatus of the same train are fed by a genand Fig. 5 represents, partly by diagram, the eral air-conduit, with which they are connectposition in which the regulator may be placed ed by branch pipes. One extremity of this with reference to the other parts of the brake conduit has a maneuvering-cock placed so apparatus of the automatic type. that the engineer may operate it. The other In appliances in usethe communication be- 75 extremity is simply closed by means of a tween the distributer of each brake apparastop-cock. When the engineer desires to aptus and the main conduit is effected bya pipe ply the brakes, he opens the cock, allowing or orifice of uniform section,and for this reaa certain quantity of air to escape from the son the brakes nearest the engine come into main conduit. Consequently a reduction of action before those at a greater distance. .80 o pressure is produced in the latter throughout This difficulty may be overcome or diminits length, and this reduction of pressure ished by automatically retarding the action bringing into play the distributers allows the of the appliances nearest the engine by a paradmission of air into the brake-cylinder from tial closing of the orifice or pipe leading to the auxiliary reservoir on each car. From the distributer or triple valve, and, 011 the 85 5 this description it will be readily understood other hand, advancing the action of those that if the main conduit is short the fall of more remote by giving said orifices an initial pressure caused by operating the maneuversection relatively large. On this principle is ing-cock will be quickly transmitted and withbased the operation of the system herein exout sensible loss throughout the whole sysplained, and which is designed to maintain 9o tem and that the brakes will operate almost the supply of air practically constant, whatsimultaneously; but this simultaneous action, ever be the variation of pressure during the deemed indispensible to secure the best reoperation between the air of the distributer sults, is not realized to the same degree when and that of the main conduit. The inventhe conduit is long, as is the case, for instance, tion therefore consists in a device interposed 5 5 in freight-trains, which consist often of from between the main conduit and the distributor, seventy to eighty vehicles. The fall of presswhich automatically adjusts the size of the ure is in such case greater at the forward orifice through which the air passes to and than at the rear end of the train, causing from the same in such manner that the size irregularities in applying the brakes, and of the orifice or passage is diminished in in- I00 jerks and strains more or less violent in the verse ratio to the degree of fluctuation of train. What has been said regarding the pressure. Thus in the brakes most remote from the engine, where the change of pressure in setting or releasing the brakes is minimum, the size of the passage or orifice is the greatest, thus compensating for the diminution of the change of pressure. The passage or orifice is formed in part by a movable piece, whose position with respect to the fixed piece forming the other part of the orifice is regulated by an actuating devicesuch asa flexible diaphragm orpistonmcved in one direction or the other by variations in pressure on the opposite sides thereof. This principle may obviously be embodied in many different forms of construction.

Asshown in the drawings, the regulating apparatus comprises two chambers A and 0, between which is a flexible but hermetic diaphragm J. The upper chamber A is in direct connection with the distributer by the passage B. The lower chamber 0 is in communication with the main conduit by orifice N. The two chambers, moreover, are in communication with each other through small channels D E F G H. Against the central rod 1, to which is attached the diaphragm J, is pressed with constant pressure a small stationary Valve K, whose lower edge or flange L is opposite to the greatest section of a groove m at when the brakes are released, thus forming the passage 11. In the lower chamber 0 are two helical springs r s, which are compressed under the action of the diaphragm when the latter is depressed and react to restore it to its normal position. The small spring r alone is utilized in the normal operation of the brake. The auxiliary spring 8 is put in action only in case of rupture of the main conduit, as will be seen hereafter. During the normal running of the train the air-pressure is the same in the two chambers A and C, and in this condition the channel II presents to the flow of air its greatest section; but as soon as the engineer opens the regulating-cock the sudden fall of pressure produced in the main conduit, and consequently in the lower chamber 0 of the regulator, causes immediately the descent of the diaphragm 0f the central rod I, with which it is connected. This section of passage in the groove m n is diminished in proportion to the movement of the rod, becoming less as the reduction of pressure in the conduit increases. Since the reduction of pressure in the main conduit or train-pipe gradually decreases from the point at which the regulating-cock is situated, usually on the engine at the forward end of the train, it follows that the section or groove m n of the regulators should increase proportionately the greater the distance said distributers are situated from the regulating-cock, so that the regulator which is connected with the main conduit the greatest distance from the regulatingcock will present at H an opening which has the maximum section, and vice versa, allowing proportionate quantities of air to escape therethrough. Thus will be secured simultaneous action of all the brakes, it being of course understood that the form of the section of the groove and the elasticity of the springs are adjusted to suit the conditions of working. As soon as the equality of pressure tends to establish itself upon the two sides of the diaphragm J the spring r reacts in a very short time and brings the groove back to its normal position with respect to the valve K.

The explanation given above maybe repeated with reference to the releasing of the brakes, only in this case the partial closing of the orifice takes place during the ascent of rod I, the same spring r being utilized for this operation. To complete this description we must examine the operation of the regulator when an accident causes the rupture of the main conduit, or the uncoupling of the flexible tubes which unite the ends of the conduit under the several cars. In such case, when the brakes work by compressed air the fall of pressure in the air-conduit is abrupt and excessive, and the spring 0', whose flexibility should be great, may be insuflicient to stand the pressure on the diaphragm. At this time spring 8, which is stitfer than the first, comes into play, still further closing the orifice and tending to maintain the simultaneous action of the brakes, whatever may be the damage to the conduit.

The second spring 3 is not necessary with vacuum-brakes, the reduction of pressure in in the main conduit being always less than one kilogram. The automatic regulator, of which Fig. 1 represents the general disposition, may assume various forms, according to the special application that is made thereof in each system of brakes. It may be isolated and connected with the main conduit or with the distributor by means of pipes, or may be combined with the distributor or triple valve in such a wayas to form an integral part thereof. The flexible diaphragm may be made of any suitable substance and may be varied in form and dimensions. It may be a metallic diaphragm, constituting itself a spring. Finally, it is possible to dispense altogher with the small valve K by arranging the groove upon a rod of very small diameter adjusted to slide with slight friction but without lateral play in a cylindrical part of the casing. This construction is indicated in Fig. 3, in which the rod I, of small diameter, has the grooven adjacent to the lower end of the tubular piece K, which is screwed into the top of chamber A. In this case it will be more convenient to establish communication between chambers A and C by an exterior pipe, as P, than by a passage formed through the rod I.

Other modifications may also be made without departing from the spirit of the invention.

Having now fully described the said invention, what I claim, and desire to secure by Letters Patent, is

1. An automatic regulator for air-brake systems, comprising two communicating chambers, one being connected to the main conduit and the other to the distributer, a pressure-actuated device, such as a diaphragm,between the two chambers, and a rod carried thereby and having a groove of varying area in cross-section forming part of the passage to the distributer, so that a change of pressure in the main conduit causes a proportionate contraction of such passage, substantially as described.

2. The combination of the two communicating chambers, one connected with the distributer and the other with the main conduit, a flexible diaphragm between the two chambers, and a regulating device or rod carried by said diaphragm and having a groove or depression diminishing in sectional area from the middle toward the ends, a stationary piece opposite said groove or depression and cut away to form part of an orifice through which air passes to and from the distributer, substantially as and for the purpose set forth.

3. The combination of the two communicating chambers connected, respectively,with the distributer and with the main conduit, the regulating device or rod actuated by the difference of pressure between the two chamit moves responsive to a fall of pressure in the main conduit, and an auxiliary spring which co-operates with the first to resist the motion of said regulator in case of an abnormal reduction of pressure in the main conduit, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

MARTIN LEONARD EDMOND DUVAL.

Witnesses:

RoBT. M. HOOPER, Josnrn EOWINIUX. 

